This invention relates in general to construction of air filters and in particular to a new and useful air filter for use in respirators.
The invention relates generally to a Pt catalyst on a substrate as air purification means for use in air filters. A similar air purification means is known from the ASME publication of the American Society of Mechanical Engineers, issue 77-ENAs-28. There, platinum metals on substrate materials catalyze the transformation of CO with air oxygen. This property is utilized on granulated substrates containing platinum metal as filter medium for CO filters. For many air filter applications it is desirable, however, to remove, besides CO, from the air other harmful gases also. But the CO filters containing platinum metal and having become known to date represent no or only little protection, particularly against acid gases like chlorine, hydrogen cyanide, hydrogen sulfide and similar gases. If a filter, such as a gas mask filter, heretofore was supposed to offer at the same time protection against acid gases and Co, it had to contain two different filter media. The one filter medium was effective for the separation of the acid gases, the other was a CO oxidation catalyst. Such gas mask filters are very big, heavy and cumbersome to handle.